What projectors are currently state-of-the-art when it comes to showing photographs?

I am looking for a projector with HD resolution (such as 1,920 x 1,200 pixels), that can be calibrated/profiled and shows excellent colors and contrast in a medium dark to dark environment. Image dimension should be up to 23 feet or 7 meters.

Here is an example - a BenQ - with 4500 lumens for $4K (I don't even know if that's enough for a 23 ft screen - the specs say it will project an image from 28-500 inches!) That site has lots of information. It has analog VGA input as well as HDMI (which means a computer with DVI out can drive it with an adapter) Don't know if it can be calibrated but there are photometers for front projectors. Don't know about the gamut (it's a business projector). Should be a good starting place...

Here is an example - a BenQ - with 4500 lumens for $4K (I don't even know if that's enough for a 23 ft screen - the specs say it will project an image from 28-500 inches!) That site has lots of information. It has analog VGA input as well as HDMI (which means a computer with DVI out can drive it with an adapter) Don't know if it can be calibrated but there are photometers for front projectors. Don't know about the gamut (it's a business projector). Should be a good starting place...

My projector experience is limited to home theater use.

According to this calculator 4500 lumens is enough for a 5 meter screen, although I'm skeptical - for a 7 meter screen I'd go quite a bit brighter. It's hard to have too much light power in a projector when there's ambient light. Note that projection screen material and its color can make a significant impact on perceived brightness. (edit: according to this even a 6500 lumen projector doesn't have enough brightness for a 7-meter screen.)

All modern projectors can be calibrated to a certain extent using appropriate hardware monitor or dedicated calibrators, but you have a pretty steep learning curve to do it by yourself. I'm not aware of semi-automatic calibration software like we have for monitor calibration, so you'll have to do it manually. Thankfully it creates much better results as you are able to tweak the areas of gamut/luminance/brightness/etc you prefer within delta-e parameters you decide, rather than one-size-fits-all approach the monitor calibration softwares I've used.

Rather than business projectors I'd go for a proper 1080p home theater projector as they generally have better options for calibration, especially at the price range you are required to go due to lumen and screen size requirements. Note that you require quite a bit of throw distance to get a 7 meter screen, and this varies wildly among projectors. Also, projectors that bright will make a lot of noise and heat, so you might need an enclosure or separate projection room depending on the venue. Best site for reviews is Project Central, and they have several calculators as well.

Yeah, I gulped when I saw the 23 foot screen requirement - my 9 ft (diagonal) screen is driven by 700 lumens in a dark cave, so 4500 seemed like a lot. The lumen requirement will depend somewhat on the extent of room darkening, and then there's the screen gain, audience viewing angle etc. to consider - it's quite a project to undertake!

If image quality is important, you’ll actually want to avoid DLP’s and certainly not use Lumens to compare to LCD’s with the idea that more is better. Its not.

I'd say lumens are more important in this case than anything else. A 7-meter screen is very large, and there's absolutely no point in using a ~2,000 lumen HT projector: no matter how great the image quality of the latest 1080p generation is, it's going to be entirely washed out at such size at that spec. I'd rather have a bright picture with color casts than a washed out one with perfect calibration (if it even can be achieved). Of course throwing money at the problem should fix the issue.

Having said that, differences in lumen specs and measurements are quite big, so 1 lumen from one manufacturer or tech (LCD, DLP) is not equal, so one has to do research where lumens matter.

Besides, LCD (HT) projectors have all kinds of magic features in them which are just as dubious as some DLP features, such as auto-iris (lol really?) or eco modes, or the lower-powered Cinema mode supposedly best for... cinema on my Panasonic which has horrendous color casts and calibrates much worse than the full-power mode.

Thanks to everyone for sharing their thoughts and valuable links. It appears that there is no easy solution as of now, and maybe the initial assumptions were 'too fuzzy' for a precise answer. For this, let me try to refine the specifications:

1. The projector is intended to be used for the public presentation of photographs with the highest quality (in regards to color, contrast, sharpness) possible.2. The room will be almost dark with no natural light and very dim (if any) artificial light.3. The projection screen width will be varying anywhere between 2 meters (6.5 feet) and 7 meters (23 feet). Most of the time (95%), the screen width will be between 3 and 5 meters (10 to 16 feet). We're using Stumpfl Monoblox projection screens with Flex White CI screen material (gain factor 1.02, viewing angle: +/- 50°).

We've looked at various solutions such as Canon's REALIS WUX10 (LCOS), Leica Pradovit D-1200 (DLP), or JVC DLA-X3/X7 (D-ILA) projectors, but would appreciate some insight from experienced users.